Engine systems and, in particular, exhaust gas recirculation (EGR) systems typically use one or more oxygen (O2) sensors for use in control of, among other features, operation of the engine and EGR system. These O2 sensors are trimmed O2 sensors, which provide a constant output voltage for the same O2 concentration at a specific atmospheric pressure (e.g., usually 101 Kpa). The general purpose of trimming an O2 sensor is to provide for all of such trimmed O2 sensors manufactured by a company to have the same output voltage for the same O2 concentration at the same reference pressure, which is usually atmospheric pressure. Trimmed O2 sensors provide an ability to use the same calibration for controlling/reading the O2 sensors. However, the trimmed O2 sensors are notably more expensive than corresponding untrimmed O2 sensors. Further, such trimmed O2 sensors are not compensated for drifting of the sensor output as the O2 sensor ages. Thus while conventional trimmed O2 sensors work for their intended purpose, there remains a need for improvement in the relevant art.